Power control arrangements for surgical instruments and batteries

ABSTRACT

Various embodiments are directed to battery unit for use with surgical instruments. The battery units may comprise a plurality of cells and include a translatable discharge drain. When attached to the surgical instrument, the discharge drain may electrically connect an anode of the battery unit to a cathode of the battery unit, for example, via a resistive element in order to drain the battery unit.

BACKGROUND

A growing number of surgical instruments are powered by one or morebattery cells. Such instruments include a variety of electricallypowered implements and may be used in a variety of surgicalenvironments. Battery-powered surgical instruments may includemotor-driven implements, such as cutters, graspers, and/or staplers, forexample. Battery-powered surgical instruments may also include non-motordriven implements, such as RF cutter/coagulators, ultrasoniccutter/coagulators, and/or laser cutter/coagulators, for example.Battery-powered instruments are also used now in various differentsurgical environments including, for example, endoscopic environments,laparoscopic environments, and open environments.

Battery-powered surgical instruments often utilize primary cells, whichare pre-charged and often intended for a single discharge (e.g., oneuse). Using single discharge cells avoids the difficulties associatedwith re-sterilizing and recharging cells. Primary cells, however,present challenges related to shipping, storage and disposal. Forexample, charged cells can result in hazardous waste if not properlydischarged since they may be only used once and still have significantamount of charge left. To mitigate the risks, many jurisdictions haveregulations governing the conditions under which cells may be shippedand disposed. Cells and batteries with higher amounts of stored energyare required to be shipped, stored, and disposed of with safety measuresthat are more stringent and often more expensive.

SUMMARY

Various embodiments may be directed to a surgical instrument having anend effector and a handle operatively coupled to the end effector. Thehandle may have a trigger to actuate the end effector and a battery dockthat has a protruding member. The surgical instrument may include abattery unit attachable to the battery dock, where the battery unit isin electrical contact with at least one of the handle and the endeffector when attached to the battery dock. The battery unit may have acasing and a first anode and a first cathode positioned within thecasing. The battery unit may also have a translatable discharge drain,where, upon attachment of the battery unit to the battery dock, theprotruding member contacts the discharge drain and the discharge draintranslates with respect to casing to electrically couple the first anodeof the battery unit to the first cathode of the battery.

Also, various embodiments may be directed to a surgical instrumenthaving a battery compartment. The surgical instrument may have aprotruding member positioned proximate the battery compartment a batteryunit. The battery unit may have a casing and a plurality of cellspositioned within the casing, where at least a portion of the pluralityof cells are not electrically connected to one another. The battery unitmay have a discharge switch having an open position and a closedposition, where, when in the closed position, the discharge switchelectrically couples an anode of the battery unit to a cathode of thebattery unit. The discharge switch may be mechanically biased towardsthe closed position, where the discharge switch is held in the openposition by a non-conductive portion of the casing. The discharge switchmay be translated into the closed position by the protruding member uponattachment of the battery unit into the battery compartment of thesurgical instrument.

Additionally, various embodiments may be directed to a surgical systemhaving a surgical device having a battery dock. The surgical system mayalso have a battery unit, where the battery unit has a first and secondgrouping of cells and a translatable battery drain positioned proximatethe first and second grouping of cells. The translatable battery drainmay have a first and second set of contacts; where, in a first position,the first and second set of contacts are not electrically coupled tofirst and second grouping of cells. In a second position, the first setof contacts may be electrically coupled to the first grouping of cellsand the second set of contacts is electrically coupled to the secondgrouping of cells. The translatable battery drain may translate from thefirst position to the second position upon attachment of the batteryunit to the battery dock.

DRAWINGS

The features of the various embodiments are set forth with particularityin the appended claims. The various embodiments, however, both as toorganization and methods of operation, together with advantages thereof,may best be understood by reference to the following description, takenin conjunction with the accompanying drawings as follows:

FIGS. 1 and 2 are perspective views of one embodiment of a surgicalcutting and fastening instrument.

FIG. 3 is an exploded view of one embodiment of the end effector of thesurgical cutting and fastening instrument of FIGS. 1 and 2.

FIGS. 4 and 5 are exploded views of one embodiment of the end effectorand shaft of the surgical cutting and fastening instrument of FIGS. 1and 2.

FIG. 6 is a side view of one embodiment the end effector of the surgicalcutting and fastening instrument of FIGS. 1 and 2.

FIG. 7 is an exploded view of one embodiment of a motor-drivenendocutter.

FIGS. 8 and 9 are partial perspective views of one embodiment of thehandle of the endocutter of FIG. 7.

FIG. 10 is a side view of one embodiment of the handle of the endocutterof FIG. 7.

FIG. 11 is a schematic diagram of one embodiment of an electricalcircuit of a surgical cutting and fastening instrument.

FIG. 12 is a side-view of a handle of one embodiment of a power-assistmotorized endocutter.

FIG. 13 is a side-view of a handle of another embodiment of apower-assist motorized endocutter.

FIGS. 14 and 15 show one embodiment of a closure trigger lockingmechanism.

FIG. 16 shows another embodiment of a closure trigger locking mechanism

FIGS. 17-22 show another embodiment of a closure trigger lockingmechanism.

FIGS. 23A-B show one embodiment of a universal joint (“u-joint”) thatmay be employed at the articulation point of a surgical instrument.

FIGS. 24A-B show one embodiment of a torsion cable that may be employedat an articulation point of a surgical instrument.

FIGS. 25-31 illustrate another embodiment of a motorized, two-strokesurgical cutting and fastening instrument with power assist.

FIGS. 32-36 illustrate one embodiment of a two-stroke, motorizedsurgical cutting and fastening instrument with power assist.

FIGS. 37-40 illustrate one embodiment of a motorized surgical cuttingand fastening instrument with such a tactile position feedback system.

FIGS. 41 and 42 illustrate two states of one embodiment of a variablesensor that may be used as the run motor sensor.

FIG. 43 is a partial cross-sectional view of a surgical instrument withvarious components removed for clarity.

FIGS. 44A and 4B illustrate a locking cam during various states ofoperation

FIGS. 45A, 45B and 45C show a locking cam and a gear during variousstages of operation.

FIG. 46 illustrates one embodiment of a surgical instrument.

FIGS. 47A, 47B and 47C schematically illustrate the attachment anddetachment of a battery unit to an instrument.

FIG. 48 is a graph of the voltage level of a battery unit over time, asmeasured from the time of attachment to the instrument, in accordancewith one non-limiting embodiment.

FIG. 49A is one embodiment of a simplified circuit diagram of a batteryunit comprising a drain.

FIG. 49B is another embodiment of a simplified circuit diagram of abattery unit comprising a drain

FIG. 50 is one embodiment of a simplified circuit diagram of a batteryunit comprising a first drain and a second drain.

FIGS. 51-53 are perspective views of one embodiment of a battery unit.

FIGS. 54A and 54B illustrate cross-sectional views of one embodiment ofa battery unit including a translatable drain.

FIG. 55 is a perspective view of one embodiment of a drain.

FIG. 56 illustrates a battery unit attached to a battery dock withvarious components omitted for clarity.

FIGS. 57A and 57B illustrate a battery unit with various componentsomitted for clarity.

FIGS. 58A and 58B illustrate a battery unit with various componentsomitted for clarity.

FIG. 59 is a perspective view of one embodiment of single cell batteryunit.

FIGS. 60A and 60B show internals views of the battery unit of FIG. 59during various stages of operation with various components omitted forclarity.

DESCRIPTION

Various embodiments are directed to battery powered surgical instrumentsand batteries comprising features for facilitating shipping, storage anddisposal. For example, according to one embodiment, a battery unit maycomprise at least one cell within a casing that defines a cavity. Thebattery unit may have a translatable discharge drain positionedproximate to the cavity. The drain may be moveable between an openposition and a closed position. A surgical instrument for use with thebattery unit may comprise a battery dock, battery compartment, or otherbattery-receiving portion that includes a protruding portion that isreceived by the cavity of the battery unit. Prior to attachment to thesurgical instrument, the discharge drain may be in the open position.Upon attachment of the battery unit to the surgical instrument, theprotruding portion may contact the discharge drain to translate thedrain with respect to the casing. When moved to its closed position, thedischarge drain may create a discharge circuit between an anode of thebattery unit, a cathode of the battery unit, and a resistive element,for example. From the time of attachment, the discharge circuit drainsthe energy from the battery unit. In some embodiments, the battery unitwill be almost discharged or fully discharged or after about 24 hours,for example. Generally, the use of the discharge drain helps to ensurethe voltage level of the battery unit are at or beneath acceptablelevels for disposal.

Prior to describing embodiments of the cells, batteries, battery units,and associated surgical instruments, a detailed description of anexample embodiments of a battery powered surgical instrument isprovided. Although the surgical instruments described herein comprisemotorized implements for cutting and stapling, it will be appreciatedthat the battery configurations described herein may be used with anysuitable type of electrical surgical instrument such as cutters,claspers, staplers, RF cutter/coagulators, ultrasoniccutter/coagulators, and laser cutter/coagulators, for example.

FIGS. 1 and 2 are perspective views of one embodiment of a surgicalcutting and fastening instrument 10. The illustrated embodiment is anendoscopic instrument and, in general, the embodiments of the instrument10 described herein are endoscopic surgical cutting and fasteninginstruments. It should be noted, however, that according to otherembodiments, the instrument may be a non-endoscopic surgical cutting andfastening instrument, such as a laparoscopic or open surgicalinstrument.

The surgical instrument 10 depicted in FIGS. 1 and 2 comprises a handle6, a shaft 8, and an articulating end effector 12 pivotally connected tothe shaft 8 at an articulation pivot 14. An articulation control 16 maybe provided adjacent to the handle 6 to effect rotation of the endeffector 12 about the articulation pivot 14. In the illustratedembodiment, the end effector 12 is configured to act as an endocutterfor clamping, severing and stapling tissue, although, in otherembodiments, different types of end effectors may be used, such as endeffectors for other types of surgical devices, such as graspers,cutters, staplers, clip appliers, access devices, drug/gene therapydevices, ultrasound, RF or laser devices, for example.

The handle 6 of the instrument 10 may include a closure trigger 18 and afiring trigger 20 for actuating the end effector 12. It will beappreciated that instruments having end effectors directed to differentsurgical tasks may have different numbers or types of triggers or othersuitable controls for operating the end effector 12. The end effector 12is shown separated from the handle 6 by a preferably elongate shaft 8.In one embodiment, a clinician or operator of the instrument 10 mayarticulate the end effector 12 relative to the shaft 8 by utilizing thearticulation control 16, as described in more detail in pending U.S.patent application Ser. No. 11/329,020, filed Jan. 10, 2006, entitled“Surgical Instrument Having An Articulating End Effector,” by GeoffreyC. Hueil et al., which is incorporated herein by reference in itsentirety.

The end effector 12 includes in this example, among other things, astaple channel 22 and a pivotally translatable clamping member, such asan anvil 24, which are maintained at a spacing that assures effectivestapling and severing of tissue clamped in the end effector 12. Thehandle 6 includes a pistol grip 26 towards which a closure trigger 18 ispivotally drawn by the clinician to cause clamping or closing of theanvil 24 toward the staple channel 22 of the end effector 12 to therebyclamp tissue positioned between the anvil 24 and channel 22. The firingtrigger 20 is farther outboard of the closure trigger 18. Once theclosure trigger 18 is locked in the closure position as furtherdescribed below, the firing trigger 20 may rotate slightly toward thepistol grip 26 so that it can be reached by the operator using one hand.Then the operator may pivotally draw the firing trigger 20 toward thepistol grip 26 to cause the stapling and severing of clamped tissue inthe end effector 12. In other embodiments, different types of clampingmembers besides the anvil 24 could be used, such as, for example, anopposing jaw.

It will be appreciated that the terms “proximal” and “distal” are usedherein with reference to a clinician gripping the handle 6 of aninstrument 10. Thus, the end effector 12 is distal with respect to themore proximal handle 6. It will be further appreciated that, forconvenience and clarity, spatial terms such as “vertical” and“horizontal” are used herein with respect to the drawings. However,surgical instruments are used in many orientations and positions, andthese terms are not intended to be limiting and absolute.

The closure trigger 18 may be actuated first. Once the clinician issatisfied with the positioning of the end effector 12, the clinician maydraw back the closure trigger 18 to its fully closed, locked positionproximate to the pistol grip 26. The firing trigger 20 may then beactuated. The firing trigger 20 returns to the open position (shown inFIGS. 1 and 2) when the clinician removes pressure, as described morefully below. A release button 160 on the handle 6, and in this example,on the pistol grip 26 of the handle 6, when depressed may release thelocked closure trigger 18.

FIG. 3 is an exploded view of one embodiment of the end effector 12. Asshown in the illustrated embodiment, the end effector 12 may include, inaddition to the previously-mentioned channel 22 and anvil 24, a cuttinginstrument 32, a sled 33, a staple cartridge 34 that is removably seatedin the channel 22, and a helical screw shaft 36. The cutting instrument32 may be, for example, a knife. The anvil 24 may be pivotably openedand closed at a pivot point 25 connected to the proximate end of thechannel 22. The anvil 24 may also include a tab 27 at its proximate endthat is inserted into a component of the mechanical closure system(described further below) to open and close the anvil 24. When theclosure trigger 18 is actuated, that is, drawn in by a user of theinstrument 10, the anvil 24 may pivot about the pivot point 25 into theclamped or closed position. If clamping of the end effector 12 issatisfactory, the operator may actuate the firing trigger 20, which, asexplained in more detail below, causes the knife 32 and sled 33 totravel longitudinally along the channel 22, thereby cutting tissueclamped within the end effector 12. The movement of the sled 33 alongthe channel 22 causes the staples of the staple cartridge 34 to bedriven through the severed tissue and against the closed anvil 24, whichturns the staples to fasten the severed tissue. U.S. Pat. No. 6,978,921,entitled “Surgical Stapling Instrument Incorporating An E-Beam FiringMechanism,” which is incorporated herein by reference, provides moredetails about such two-stroke cutting and fastening instruments.According to various embodiments, the sled 33 may be an integral part ofthe cartridge 34, such that when the knife 32 retracts following thecutting operation, the sled 33 does not retract.

It should be noted that although the embodiments of the instrument 10described herein employ an end effector 12 that staples the severedtissue, in other embodiments different techniques for fastening orsealing the severed tissue may be used. For example, end effectors thatuse RF energy or adhesives to fasten the severed tissue may also beused. U.S. Pat. No. 5,810,811, entitled “Electrosurgical HemostaticDevice,” which is incorporated herein by reference, discloses a cuttinginstrument that uses RF energy to fasten the severed tissue. U.S. patentapplication Ser. No. 11/267,811, entitled “Surgical Stapling InstrumentsStructured For Delivery Of Medical Agents” and U.S. patent applicationSer. No. 11/267,383, entitled “Surgical Stapling Instruments StructuredFor Pump-Assisted Delivery Of Medical Agents,” both of which are alsoincorporated herein by reference, disclose cutting instruments that useadhesives to fasten the severed tissue. Accordingly, although thedescription herein refers to cutting/stapling operations and the likebelow, it should be recognized that this is an example embodiment and isnot meant to be limiting. Other tissue-fastening techniques may also beused.

FIGS. 4 and 5 are exploded views and FIG. 6 is a side view of oneembodiment of the end effector 12 and shaft 8. As shown in theillustrated embodiment, the shaft 8 may include a proximate closure tube40 and a distal closure tube 42 pivotably linked by a pivot links 44.The distal closure tube 42 includes an opening 45 into which the tab 27on the anvil 24 is inserted in order to open and close the anvil 24, asfurther described below. Disposed inside the closure tubes 40, 42 may bea proximate spine tube 46. Disposed inside the proximate spine tube 46may be a main rotational (or proximate) drive shaft 48 that communicateswith a secondary (or distal) drive shaft 50 via a bevel gear assembly52. The secondary drive shaft 50 is connected to a drive gear 54 thatengages a proximate drive gear 56 of the helical screw shaft 36. Whenthe main drive shaft 48 is caused to rotate by actuation of the firingtrigger 20 (as explained in more detail below), the bevel gear assembly52 a-c causes the secondary drive shaft 50 to rotate, which in turn,because of the engagement of the drive gears 54, 56, causes the helicalscrew shaft 36 to rotate, which causes the knife/sled driving member 32to travel longitudinally along the channel 22 to cut any tissue clampedwithin the end effector 12. The vertical bevel gear 52 b may sit andpivot in an opening 57 in the distal end of the proximate spine tube 46.A distal spine tube 58 may be used to enclose the secondary drive shaft50 and the drive gears 54, 56. Collectively, the main drive shaft 48,the secondary drive shaft 50, and the articulation assembly (e.g., thebevel gear assembly 52 a-c) are sometimes referred to herein as the“main drive shaft assembly.”

A bearing 38 is threaded on the helical drive screw 36. The bearing 36is also connected to the knife 32. When the helical drive screw 36forward rotates, the bearing 38 traverses the helical drive screw 36distally, driving the cutting instrument 32 and, in the process, thesled 33 to perform the cutting/stapling operation. The sled 33 may bemade of, for example, plastic, and may have a sloped distal surface. Asthe sled 33 traverses the channel 22, the sloped forward surface maypush up or drive the staples in the staple cartridge 34 through theclamped tissue and against the anvil 24. The anvil 24 turns the staples,thereby stapling the severed tissue. When the knife 32 is retracted, theknife 32 and sled 33 may become disengaged, thereby leaving the sled 33at the distal end of the channel 22.

Because of the lack of user feedback for the cutting/stapling operation,there is a general lack of acceptance among physicians of motor-drivensurgical instruments where the cutting/stapling operation is actuated bymerely pressing a button. In contrast, various embodiments may provide amotor-driven endocutter with user-feedback of the deployment, force,and/or position of the cutting instrument in the end effector.

FIGS. 7-10 illustrate one embodiment of a motor-driven endocutter, andin particular the handle 6 thereof, that provides user-feedbackregarding the deployment and loading force of the cutting instrument inthe end effector. In addition, the embodiment may use power provided bythe user in retracting the firing trigger 20 to power the device (aso-called “power assist” mode). As shown in the illustrated embodiment,the handle 6 includes exterior lower side pieces 59, 60 and exteriorupper side pieces 61, 62 that fit together to form, in general, theexterior of the handle 6. A battery 64, such as a Li ion battery, may beprovided in a battery dock 63. In some embodiments, the battery 64 isprovided in the pistol grip portion 26 of the handle 6. Although thebattery 64 is illustrated as containing multiple cells connectedtogether, it is to be appreciated that the battery 64, in someembodiments, may include a single cell. The battery 64 may power a motor65 disposed in an upper portion of the pistol grip portion 26 of thehandle 6. According to various embodiments, the motor 65 may be a DCbrushed driving motor having a maximum rotation of, approximately, 5000RPM. The motor 65 may drive a 90° bevel gear assembly 66 comprising afirst bevel gear 68 and a second bevel gear 70. The bevel gear assembly66 may drive a planetary gear assembly 72. The planetary gear assembly72 may include a pinion gear 74 connected to a drive shaft 76. Thepinion gear 74 may drive a mating ring gear 78 that drives a helicalgear drum 80 via a drive shaft 82. A ring 84 may be threaded on thehelical gear drum 80. Thus, when the motor 65 rotates, the ring 84 iscaused to travel along the helical gear drum 80 by means of theinterposed bevel gear assembly 66, planetary gear assembly 72 and ringgear 78.

The handle 6 may also include a run motor sensor 110 in communicationwith the firing trigger 20 to detect when the firing trigger 20 has beendrawn in (or “closed”) toward the pistol grip portion 26 of the handle 6by the operator to thereby actuate the cutting/stapling operation by theend effector 12. The sensor 110 may be a proportional sensor such as,for example, a rheostat or variable resistor. When the firing trigger 20is drawn in, the sensor 110 detects the movement, and sends anelectrical signal indicative of the voltage (or power) to be supplied tothe motor 65. When the sensor 110 is a variable resistor or the like,the rotation of the motor 65 may be generally proportional to the amountof movement of the firing trigger 20. That is, if the operator onlydraws or closes the firing trigger 20 in a little bit, the rotation ofthe motor 65 is relatively low. When the firing trigger 20 is fullydrawn in (or in the fully closed position), the rotation of the motor 65is at its maximum. In other words, the harder the user pulls on thefiring trigger 20, the more voltage is applied to the motor 65, causinggreater rates of rotation.

The handle 6 may include a middle handle piece 104 adjacent to the upperportion of the firing trigger 20. The handle 6 also may comprise a biasspring 112 connected between posts on the middle handle piece 104 andthe firing trigger 20. The bias spring 112 may bias the firing trigger20 to its fully open position. In that way, when the operator releasesthe firing trigger 20, the bias spring 112 will pull the firing trigger20 to its open position, thereby removing actuation of the sensor 110,thereby stopping rotation of the motor 65. Moreover, by virtue of thebias spring 112, any time a user closes the firing trigger 20, the userwill experience resistance to the closing operation, thereby providingthe user with feedback as to the amount of rotation exerted by the motor65. Further, the operator could stop retracting the firing trigger 20 tothereby remove force from the sensor 100, to thereby stop the motor 65.As such, the user may stop the deployment of the end effector 12,thereby providing a measure of control of the cutting/fasteningoperation to the operator.

The distal end of the helical gear drum 80 includes a distal drive shaft120 that drives a ring gear 122, which mates with a pinion gear 124. Thepinion gear 124 is connected to the main drive shaft 48 of the maindrive shaft assembly. In that way, rotation of the motor 65 causes themain drive shaft assembly to rotate, which causes actuation of the endeffector 12, as described above.

The ring 84 threaded on the helical gear drum 80 may include a post 86that is disposed within a slot 88 of a slotted arm 90. The slotted arm90 has an opening 92 its opposite end 94 that receives a pivot pin 96that is connected between the handle exterior side pieces 59, 60. Thepivot pin 96 is also disposed through an opening 100 in the firingtrigger 20 and an opening 102 in the middle handle piece 104.

In addition, the handle 6 may include a reverse motor (or end-of-strokesensor) 130 and a stop motor (or beginning-of-stroke) sensor 142. Invarious embodiments, the reverse motor sensor 130 may be a limit switchlocated at the distal end of the helical gear drum 80 such that the ring84 threaded on the helical gear drum 80 contacts and trips the reversemotor sensor 130 when the ring 84 reaches the distal end of the helicalgear drum 80. The reverse motor sensor 130, when activated, sends asignal to the motor 65 to reverse its rotation direction, therebywithdrawing the knife 32 of the end effector 12 following the cuttingoperation.

The stop motor sensor 142 may be, for example, a normally-closed limitswitch. In various embodiments, it may be located at the proximate endof the helical gear drum 80 so that the ring 84 trips the switch 142when the ring 84 reaches the proximate end of the helical gear drum 80.

In operation, when an operator of the instrument 10 pulls back thefiring trigger 20, the sensor 110 detects the deployment of the firingtrigger 20 and sends a signal to the motor 65 to cause forward rotationof the motor 65 at, for example, a rate proportional to how hard theoperator pulls back the firing trigger 20. The forward rotation of themotor 65 in turn causes the ring gear 78 at the distal end of theplanetary gear assembly 72 to rotate, thereby causing the helical geardrum 80 to rotate, causing the ring 84 threaded on the helical gear drum80 to travel distally along the helical gear drum 80. The rotation ofthe helical gear drum 80 also drives the main drive shaft assembly asdescribed above, which in turn causes deployment of the knife 32 in theend effector 12. That is, the knife 32 and sled 33 are caused totraverse the channel 22 longitudinally, thereby cutting tissue clampedin the end effector 12. Also, the stapling operation of the end effector12 is caused to happen in embodiments where a stapling-type end effectoris used.

By the time the cutting/stapling operation of the end effector 12 iscomplete, the ring 84 on the helical gear drum 80 will have reached thedistal end of the helical gear drum 80, thereby causing the reversemotor sensor 130 to be tripped, which sends a signal to the motor 65 tocause the motor 65 to reverse its rotation. This in turn causes theknife 32 to retract, and also causes the ring 84 on the helical geardrum 80 to move back to the proximate end of the helical gear drum 80.

The middle handle piece 104 includes a backside shoulder 106 thatengages the slotted arm 90 as best shown in FIGS. 8 and 9. The middlehandle piece 104 also has a forward motion stop 107 that engages thefiring trigger 20. The movement of the slotted arm 90 is controlled, asexplained above, by rotation of the motor 65. When the slotted arm 90rotates CCW as the ring 84 travels from the proximate end of the helicalgear drum 80 to the distal end, the middle handle piece 104 will be freeto rotate CCW. Thus, as the user draws in the firing trigger 20, thefiring trigger 20 will engage the forward motion stop 107 of the middlehandle piece 104, causing the middle handle piece 104 to rotate CCW. Dueto the backside shoulder 106 engaging the slotted arm 90, however, themiddle handle piece 104 will only be able to rotate CCW as far as theslotted arm 90 permits. In that way, if the motor 65 should stoprotating for some reason, the slotted arm 90 will stop rotating, and theuser will not be able to further draw in the firing trigger 20 becausethe middle handle piece 104 will not be free to rotate CCW due to theslotted arm 90.

FIGS. 41 and 42 illustrate two states of one embodiment of a variablesensor that may be used as the run motor sensor 110. The sensor 110 mayinclude a face portion 280, a first electrode (A) 282, a secondelectrode (B) 284, and a compressible dielectric material 286 (e.g.,EAP) between the electrodes 282, 284. The sensor 110 may be positionedsuch that the face portion 280 contacts the firing trigger 20 whenretracted. Accordingly, when the firing trigger 20 is retracted, thedielectric material 286 is compressed, as shown in FIG. 42, such thatthe electrodes 282, 284 are closer together. Since the distance “b”between the electrodes 282, 284 is directly related to the impedancebetween the electrodes 282, 284, the greater the distance the moreimpedance, and the closer the distance the less impedance. In that way,the amount that the dielectric material 286 is compressed due toretraction of the firing trigger 20 (denoted as force “F” in FIG. 42) isproportional to the impedance between the electrodes 282, 284, which canbe used to proportionally control the motor 65.

Components of an example closure system for closing (or clamping) theanvil 24 of the end effector 12 by retracting the closure trigger 18 arealso shown in FIGS. 7-10. In the illustrated embodiment, the closuresystem includes a yoke 250 connected to the closure trigger 18 by a pin251 that is inserted through aligned openings in both the closuretrigger 18 and the yoke 250. A pivot pin 252, about which the closuretrigger 18 pivots, is inserted through another opening in the closuretrigger 18 which is offset from where the pin 251 is inserted throughthe closure trigger 18. Thus, retraction of the closure trigger 18causes the upper part of the closure trigger 18, to which the yoke 250is attached via the pin 251, to rotate CCW. The distal end of the yoke250 is connected, via a pin 254, to a first closure bracket 256. Thefirst closure bracket 256 connects to a second closure bracket 258.Collectively, the closure brackets 256, 258 define an opening in whichthe proximate end of the proximate closure tube 40 (see FIG. 4) isseated and held such that longitudinal movement of the closure brackets256, 258 causes longitudinal motion by the proximate closure tube 40.The instrument 10 also includes a closure rod 260 disposed inside theproximate closure tube 40. The closure rod 260 may include a window 261into which a post 263 on one of the handle exterior pieces, such asexterior lower side piece 59 in the illustrated embodiment, is disposedto fixedly connect the closure rod 260 to the handle 6. In that way, theproximate closure tube 40 is capable of moving longitudinally relativeto the closure rod 260. The closure rod 260 may also include a distalcollar 267 that fits into a cavity 269 in proximate spine tube 46 and isretained therein by a cap 271 (see FIG. 4).

In operation, when the yoke 250 rotates due to retraction of the closuretrigger 18, the closure brackets 256, 258 cause the proximate closuretube 40 to move distally (e.g., away from the handle end of theinstrument 10), which causes the distal closure tube 42 to movedistally, which causes the anvil 24 to rotate about the pivot point 25into the clamped or closed position. When the closure trigger 18 isunlocked from the locked position, the proximate closure tube 40 iscaused to slide proximally, which causes the distal closure tube 42 toslide proximally, which by virtue of the tab 27 being inserted in thewindow 45 of the distal closure tube 42, causes the anvil 24 to pivotabout the pivot point 25 into the open or unclamped position. In thatway, by retracting and locking the closure trigger 18, an operator mayclamp tissue between the anvil 24 and channel 22, and may unclamp thetissue following the cutting/stapling operation by unlocking the closuretrigger 18 from the locked position.

FIG. 11 is a schematic diagram of one embodiment of an electricalcircuit of the instrument 10. When an operator initially pulls in thefiring trigger 20 after locking the closure trigger 18, the sensor 110is activated, allowing current to flow therethrough. If thenormally-open reverse motor sensor switch 130 is open (meaning the endof the end effector stroke has not been reached), current will flow to asingle pole, double throw relay 132. Since the reverse motor sensorswitch 130 is not closed, the coil 134 of the relay 132 will not beenergized, so the relay 132 will be in its non-energized state. Thecircuit also includes a cartridge lockout sensor switch 136. If the endeffector 12 includes a staple cartridge 34, the sensor switch 136 willbe in the closed state, allowing current to flow. Otherwise, if the endeffector 12 does not include a staple cartridge 34, the sensor switch136 will be open, thereby preventing the battery 64 from powering themotor 65. As discussed in the more detail below, when the battery 64 isinserted into the instrument 10, a resistive element 65 may be connectedinto the electrical circuit to discharge the battery 64.

When the staple cartridge 34 is present, the sensor switch 136 isclosed, which energizes a single pole, single throw relay 138. When therelay 138 is energized, current flows through the relay 138, through thevariable resistor sensor 110, and to the motor 65 via a double pole,double throw relay 140, thereby powering the motor 65 and allowing it torotate in the forward direction.

When the end effector 12 reaches the end of its stroke, the reversemotor sensor 130 will be activated, thereby closing the switch 130 andenergizing the relay 132. This causes the relay 132 to assume itsenergized state (not shown in FIG. 11), which causes current to bypassthe cartridge lockout sensor switch 136 and variable resistor 110, andinstead causes current to flow to both the normally-closed double pole,double throw relay 140 and back to the motor 65, but in a manner, viathe relay 140, that causes the motor 65 to reverse its rotationaldirection.

Because the stop motor sensor switch 142 is normally-closed, currentwill flow back to the relay 132 to keep it energized until the switch142 opens. When the knife 32 is fully retracted, the stop motor sensorswitch 142 is activated, causing the switch 142 to open, therebyremoving power from the motor 65.

In other embodiments, rather than a proportional-type sensor 110, anon-off type sensor could be used. In such embodiments, the rate ofrotation of the motor 65 would not be proportional to the force appliedby the operator. Rather, the motor 65 would generally rotate at aconstant rate. But the operator would still experience force feedbackbecause the firing trigger 20 is geared into the gear drive train.

FIG. 12 is a side-view of the handle 6 of a power-assist motorizedendocutter according to another embodiment. The embodiment of FIG. 12 issimilar to that of FIGS. 7-10 except that in the embodiment of FIG. 12,there is no slotted arm 90 connected to the ring 84 threaded on thehelical gear drum 80. Instead, in the embodiment of FIG. 12, the ring 84includes a sensor portion 114 that moves with the ring 84 as the ring 84advances down (and back) on the helical gear drum 80. The sensor portion114 includes a notch 116. The reverse motor sensor 130 may be located atthe distal end of the notch 116 and the stop motor sensor 142 may belocated at the proximate end of the notch 116. As the ring 84 moves downthe helical gear drum 80 (and back), the sensor portion 114 moves withit. Further, as shown in FIG. 12, the middle piece 104 may have an arm118 that extends into the notch 116.

In operation, as an operator of the instrument 10 retracts in the firingtrigger 20 toward the pistol grip 26, the run motor sensor 110 detectsthe motion and sends a signal to power the motor 65, which causes, amongother things, the helical gear drum 80 to rotate. As the helical geardrum 80 rotates, the ring 84 threaded on the helical gear drum 80advances (or retracts, depending on the rotation). Also, due to thepulling in of the firing trigger 20, the middle piece 104 is caused torotate CCW with the firing trigger 20 due to the forward motion stop 107that engages the firing trigger 20. The CCW rotation of the middle piece104 cause the arm 118 to rotate CCW with the sensor portion 114 of thering 84 such that the arm 118 stays disposed in the notch 116. When thering 84 reaches the distal end of the helical gear drum 80, the arm 118will contact and thereby trip the reverse motor sensor 130. Similarly,when the ring 84 reaches the proximate end of the helical gear drum 80,the arm 118 will contact and thereby trip the stop motor sensor 142.Such actions may reverse and stop the motor 65, respectively, asdescribed above.

FIG. 13 is a side-view of the handle 6 of a power-assist motorizedendocutter according to another embodiment. The embodiment of FIG. 13 issimilar to that of FIGS. 7-10 except that in the embodiment of FIG. 13,there is no slot in the arm 90. Instead, the ring 84 threaded on thehelical gear drum 80 includes a vertical channel 126. Instead of a slot,the aim 90 includes a post 128 that is disposed in the channel 126. Asthe helical gear drum 80 rotates, the ring 84 threaded on the helicalgear drum 80 advances (or retracts, depending on the rotation). The arm90 rotates CCW as the ring 84 advances due to the post 128 beingdisposed in the channel 126, as shown in FIG. 13.

As mentioned above, in using a two-stroke motorized instrument, theoperator first pulls back and locks the closure trigger 18. FIGS. 14 and15 show one embodiment of a closure trigger 18 locking mechanism forlocking the closure trigger 18 to the pistol grip portion 26 of thehandle 6. In the illustrated embodiment, the pistol grip portion 26includes a hook 150 that is biased to rotate CCW about a pivot point 151by a torsion spring 152. Also, the closure trigger 18 includes a closurebar 154. As the operator draws in the closure trigger 18, the closurebar 154 engages a sloped portion 156 of the hook 150, thereby rotatingthe hook 150 upward (or CW in FIGS. 14-15) until the closure bar 154completely passes the sloped portion 156 into a recessed notch 158 ofthe hook 150, which locks the closure trigger 18 in place. The operatormay release the closure trigger 18 by pushing down on a slide buttonrelease 160 on the back or opposite side of the pistol grip portion 26.Pushing down the slide button release 160 rotates the hook 150 CW suchthat the closure bar 154 is released from the recessed notch 158.

FIG. 16 shows another closure trigger locking mechanism according tovarious embodiments. In the embodiment of FIG. 16, the closure trigger18 includes a wedge 160 having an arrow-head portion 161. The arrow-headportion 161 is biased downward (or CW) by a leaf spring 162. The wedge160 and leaf spring 162 may be made from, for example, molded plastic.When the closure trigger 18 is retracted, the arrow-head portion 161 isinserted through an opening 164 in the pistol grip portion 26 of thehandle 6. A lower chamfered surface 166 of the arrow-head portion 161engages a lower sidewall 168 of the opening 164, forcing the arrow-headportion 161 to rotate CCW. Eventually the lower chamfered surface 166fully passes the lower sidewall 168, removing the CCW force on thearrow-head portion 161, causing the lower sidewall 168 to slip into alocked position in a notch 170 behind the arrow-head portion 161.

To unlock the closure trigger 18, a user presses down on a button 172 onthe opposite side of the closure trigger 18, causing the arrow-headportion 161 to rotate CCW and allowing the arrow-head portion 161 toslide out of the opening 164.

FIGS. 17-22 show another embodiment of a closure trigger lockingmechanism. As shown in this embodiment, the closure trigger 18 includesa flexible longitudinal arm 176 that includes a lateral pin 178extending therefrom. The arm 176 and pin 178 may be made from moldedplastic, for example. The pistol grip portion 26 of the handle 6includes an opening 180 with a laterally extending wedge 182 disposedtherein. When the closure trigger 18 is retracted, the pin 178 engagesthe wedge 182, and the pin 178 is forced downward (e.g., the arm 176 isrotated CW) by the lower surface 184 of the wedge 182, as shown in FIGS.17 and 18. When the pin 178 fully passes the lower surface 184, the CWforce on the arm 176 is removed, and the pin 178 is rotated CCW suchthat the pin 178 comes to rest in a notch 186 behind the wedge 182, asshown in FIG. 19, thereby locking the closure trigger 18. The pin 178 isfurther held in place in the locked position by a flexible stop 188extending from the wedge 184.

To unlock the closure trigger 18, the operator may further squeeze theclosure trigger 18, causing the pin 178 to engage a sloped backwall 190of the opening 180, forcing the pin 178 upward past the flexible stop188, as shown in FIGS. 20 and 21. The pin 178 is then free to travel outan upper channel 192 in the opening 180 such that the closure trigger 18is no longer locked to the pistol grip portion 26, as shown in FIG. 22.

FIGS. 23A-B show a universal joint (“u-joint”) 195 that may be employedat the articulation point of a surgical instrument, such as theinstrument 10. The second piece 195-2 of the u-joint 195 rotates in ahorizontal plane in which the first piece 195-1 lies. FIG. 23A shows theu-joint 195 in a linear (180°) orientation and FIG. 23B shows theu-joint 195 at approximately a 150° orientation. The u-joint 195 may beused instead of the bevel gears 52 a-c (see FIG. 4, for example) at thearticulation point 14 of the main drive shaft assembly to articulate theend effector 12. FIGS. 24A-B show a torsion cable 197 that may be usedin lieu of both the bevel gears 52 a-c and the u-joint 195 to realizearticulation of the end effector 12.

FIGS. 25-31 illustrate another embodiment of a motorized, two-strokesurgical cutting and fastening instrument 10 with power assist. Theembodiment of FIGS. 25-31 is similar to that of FIGS. 6-10 except thatinstead of the helical gear drum 80, the embodiment of FIGS. 25-31includes an alternative gear drive assembly. The embodiment of FIGS.25-31 includes a gear box assembly 200 including a number of gearsdisposed in a frame 201, wherein the gears are connected between theplanetary gear 72 and the pinion gear 124 at the proximate end of thedrive shaft 48. As explained further below, the gear box assembly 200provides feedback to the user via the firing trigger 20 regarding thedeployment and loading force of the end effector 12. Also, the user mayprovide power to the system via the gear box assembly 200 to assist thedeployment of the end effector 12. In that sense, like the embodimentsdescribed above, the embodiment of FIGS. 25-31 is another power assist,motorized instrument 10 that provides feedback to the user regarding theloading force experienced by the cutting instrument 32.

In the illustrated embodiment, the firing trigger 20 includes twopieces: a main body portion 202 and a stiffening portion 204. The mainbody portion 202 may be made of plastic, for example, and the stiffeningportion 204 may be made out of a more rigid material, such as metal. Inthe illustrated embodiment, the stiffening portion 204 is adjacent tothe main body portion 202, but according to other embodiments, thestiffening portion 204 could be disposed inside the main body portion202. A pivot pin 207 may be inserted through openings in the firingtrigger pieces 202, 204 and may be the point about which the firingtrigger 20 rotates. In addition, a spring 222 may bias the firingtrigger 20 to rotate in a CCW direction. The spring 222 may have adistal end connected to a pin 224 that is connected to the pieces 202,204 of the firing trigger 20. The proximate end of the spring 222 may beconnected to one of the handle exterior lower side pieces 59, 60.

In the illustrated embodiment, both the main body portion 202 and thestiffening portion 204 include gear portions 206, 208 (respectively) attheir upper end portions. The gear portions 206, 208 engage a gear inthe gear box assembly 200, as explained below, to drive the main driveshaft assembly and to provide feedback to the user regarding thedeployment of the end effector 12.

The gear box assembly 200 may include as shown, in the illustratedembodiment, six (6) gears. A first gear 210 of the gear box assembly 200engages the gear portions 206, 208 of the firing trigger 20. Inaddition, the first gear 210 engages a smaller second gear 212, thesmaller second gear 212 being coaxial with a large third gear 214. Thethird gear 214 engages a smaller fourth gear 216, the smaller fourthgear 216 being coaxial with a fifth gear 218. The fifth gear 218 is a90° bevel gear that engages a mating 90° bevel gear 220 (best shown inFIG. 31) that is connected to the pinion gear 124 that drives the maindrive shaft 48.

In operation, when the user retracts the firing trigger 20, a run motorsensor (not shown) is activated, which may provide a signal to the motor65 to rotate at a rate proportional to the extent or force with whichthe operator is retracting the firing trigger 20. This causes the motor65 to rotate at a speed proportional to the signal from the sensor. Thesensor is not shown for this embodiment, but it could be similar to therun motor sensor 110 described above. The sensor could be located in thehandle 6 such that it is depressed when the firing trigger 20 isretracted. Also, instead of a proportional-type sensor, an on/off typesensor may be used.

Rotation of the motor 65 causes the bevel gears 66, 70 to rotate, whichcauses the planetary gear 72 to rotate, which causes, via the driveshaft 76, the ring gear 122 to rotate. The ring gear 122 meshes with thepinion gear 124, which is connected to the main drive shaft 48. Thus,rotation of the pinion gear 124 drives the main drive shaft 48, whichcauses actuation of the cutting/stapling operation of the end effector12.

Forward rotation of the pinion gear 124 in turn causes the bevel gear220 to rotate, which causes, by way of the rest of the gears of the gearbox assembly 200, the first gear 210 to rotate. The first gear 210engages the gear portions 206, 208 of the firing trigger 20, therebycausing the firing trigger 20 to rotate CCW when the motor 65 providesforward drive for the end effector 12 (and to rotate CCW when the motor65 rotates in reverse to retract the end effector 12). In that way, theuser experiences feedback regarding loading force and deployment of theend effector 12 by way of the user's grip on the firing trigger 20.Thus, when the user retracts the firing trigger 20, the operator willexperience a resistance related to the load force experienced by the endeffector 12. Similarly, when the operator releases the firing trigger 20after the cutting/stapling operation so that it can return to itsoriginal position, the user will experience a CW rotation force from thefiring trigger 20 that is generally proportional to the reverse speed ofthe motor 65.

It should also be noted that in this embodiment the user can apply force(either in lieu of or in addition to the force from the motor 65) toactuate the main drive shaft assembly (and hence the cutting/staplingoperation of the end effector 12) through retracting the firing trigger20. That is, retracting the firing trigger 20 causes the gear portions206, 208 to rotate CCW, which causes the gears of the gear box assembly200 to rotate, thereby causing the pinion gear 124 to rotate, whichcauses the main drive shaft 48 to rotate.

Although not shown in FIGS. 25-31, the instrument 10 may further includereverse motor and stop motor sensors. As described above, the reversemotor and stop motor sensors may detect, respectively, the end of thecutting stroke (full deployment of the knife 32 and sled 33) and the endof retraction operation (full retraction of the knife 32). A circuitsimilar to that described above in connection with FIG. 11 may be usedto appropriately power the motor 65.

FIGS. 32-36 illustrate another embodiment of a two-stroke, motorizedsurgical cutting and fastening instrument 10 with power assist. Theembodiment of FIGS. 32-36 is similar to that of FIGS. 25-31 except thatin the embodiment of FIGS. 32-36, the firing trigger 20 includes a lowerportion 228 and an upper portion 230. Both portions 228, 230 areconnected to and pivot about a pivot pin 207 that is disposed througheach portion 228, 230. The upper portion 230 includes a gear portion 232that engages the first gear 210 of the gear box assembly 200. The spring222 is connected to the upper portion 230 such that the upper portion isbiased to rotate in the CW direction. The upper portion 230 may alsoinclude a lower arm 234 that contacts an upper surface of the lowerportion 228 of the firing trigger 20 such that when the upper portion230 is caused to rotate CW the lower portion 228 also rotates CW, andwhen the lower portion 228 rotates CCW the upper portion 230 alsorotates CCW. Similarly, the lower portion 228 includes a rotational stop238 that engages a lower shoulder of the upper portion 230. In that way,when the upper portion 230 is caused to rotate CCW the lower portion 228also rotates CCW, and when the lower portion 228 rotates CW the upperportion 230 also rotates CW.

The illustrated embodiment also includes the run motor sensor 110 thatcommunicates a signal to the motor 65 that, in various embodiments, maycause the motor 65 to rotate at a speed proportional to the forceapplied by the operator when retracting the firing trigger 20. Thesensor 110 may be, for example, a rheostat or some other variableresistance sensor, as explained herein. In addition, the instrument 10may include a reverse motor sensor 130 that is tripped or switched whencontacted by a front face 242 of the upper portion 230 of the firingtrigger 20. When activated, the reverse motor sensor 130 sends a signalto the motor 65 to reverse direction. Also, the instrument 10 mayinclude a stop motor sensor 142 that is tripped or actuated whencontacted by the lower portion 228 of the firing trigger 20. Whenactivated, the stop motor sensor 142 sends a signal to stop the reverserotation of the motor 65.

In operation, when an operator retracts the closure trigger 18 into thelocked position, the firing trigger 20 is retracted slightly (throughmechanisms known in the art, including U.S. Pat. No. 6,978,921, entitled“Surgical Stapling Instrument Incorporating An E-Beam Firing Mechanism”and U.S. Pat. No. 6,905,057, entitled “Surgical Stapling InstrumentIncorporating A Firing Mechanism Having A Linked Rack Transmission,”both of which are incorporated herein by reference) so that the user cangrasp the firing trigger 20 to initiate the cutting/stapling operation,as shown in FIGS. 32 and 33. At that point, as shown in FIG. 33, thegear portion 232 of the upper portion 230 of the firing trigger 20 movesinto engagement with the first gear 210 of the gear box assembly 200.When the operator retracts the firing trigger 20, according to variousembodiments, the firing trigger 20 may rotate a small amount, such asfive degrees, before tripping the run motor sensor 110, as shown in FIG.34. Activation of the sensor 110 causes the motor 65 to forward rotateat a rate proportional to the retraction force applied by the operator.The forward rotation of the motor 65 causes, as described above, themain drive shaft 48 to rotate, which causes the knife 32 in the endeffector 12 to be deployed (e.g., begin traversing the channel 22).Rotation of the pinion gear 124, which is connected to the main driveshaft 48, causes the gears 210-220 in the gear box assembly 200 torotate. Since the first gear 210 is in engagement with the gear portion232 of the upper portion 230 of the firing trigger 20, the upper portion230 is caused to rotate CCW, which causes the lower portion 228 to alsorotate CCW.

When the knife 32 is fully deployed (e.g., at the end of the cuttingstroke), the front face 242 of the upper portion 230 trips the reversemotor sensor 130, which sends a signal to the motor 65 to reverserotational direction. This causes the main drive shaft assembly toreverse rotational direction to retract the knife 32. Reverse rotationof the main drive shaft assembly causes the gears 210-220 in the gearbox assembly to reverse direction, which causes the upper portion 230 ofthe firing trigger 20 to rotate CW, which causes the lower portion 228of the firing trigger 20 to rotate CW until the front face 242 of theupper portion 230 trips or actuates the stop motor sensor 142 when theknife 32 is fully retracted, which causes the motor 65 to stop. In thatway, the user experiences feedback regarding deployment of the endeffector 12 by way of the user's grip on the firing trigger 20. Thus,when the user retracts the firing trigger 20, the operator willexperience a resistance related to the deployment of the end effector 12and, in particular, to the loading force experienced by the knife 32.Similarly, when the operator releases the firing trigger 20 after thecutting/stapling operation so that it can return to its originalposition, the user will experience a CW rotation force from the firingtrigger 20 that is generally proportional to the reverse speed of themotor 65.

It should also be noted that in this embodiment the user can apply force(either in lieu of or in addition to the force from the motor 65) toactuate the main drive shaft assembly (and hence the cutting/staplingoperation of the end effector 12) through retracting the firing trigger20. That is, retracting the firing trigger 20 causes the gear portion232 of the upper portion 230 to rotate CCW, which causes the gears ofthe gear box assembly 200 to rotate, thereby causing the pinion gear 124to rotate, which causes the main drive shaft assembly to rotate.

The above-described embodiments employed power-assist user feedbacksystems, with or without adaptive control (e.g., using a sensor 110,130, and 142 outside of the closed loop system of the motor, gear drivetrain, and end effector) for a two-stroke, motorized surgical cuttingand fastening instrument. That is, force applied by the user inretracting the firing trigger 20 may be added to the force applied bythe motor 65 by virtue of the firing trigger 20 being geared into(either directly or indirectly) the gear drive train between the motor65 and the main drive shaft 48. In other embodiments, the user may beprovided with tactile feedback regarding the position of the knife 32 inthe end effector 12, but without having the firing trigger 20 gearedinto the gear drive train. FIGS. 37-40 illustrate one embodiment of amotorized surgical cutting and fastening instrument 10 with such atactile position feedback system.

In the illustrated embodiment of FIGS. 37-40, the firing trigger 20 mayhave a lower portion 228 and an upper portion 230, similar to theinstrument 10 shown in FIGS. 32-36. Unlike the embodiment of FIG. 32-36,however, the upper portion 230 does not have a gear portion that mateswith part of the gear drive train. Instead, the instrument 10 includes asecond motor 265 with a threaded rod 266 threaded therein. The threadedrod 266 reciprocates longitudinally in and out of the motor 265 as themotor 265 rotates, depending on the direction of rotation. Theinstrument 10 also includes an encoder 268 that is responsive to therotations of the main drive shaft 48 for translating the incrementalangular motion of the main drive shaft 48 (or other component of themain drive assembly) into a corresponding series of digital signals, forexample. In the illustrated embodiment, the pinion gear 124 includes aproximate drive shaft 270 that connects to the encoder 268.

The instrument 10 also includes a control circuit (not shown), which maybe implemented using a microcontroller or some other type of integratedcircuit, that receives the digital signals from the encoder 268. Basedon the signals from the encoder 268, the control circuit may calculatethe stage of deployment of the knife 32 in the end effector 12. That is,the control circuit can calculate if the knife 32 is fully deployed,fully retracted, or at an intermittent stage. Based on the calculationof the stage of deployment of the end effector 12, the control circuitmay send a signal to the second motor 265 to control its rotation tothereby control the reciprocating movement of the threaded rod 266.

In operation, as shown in FIG. 37, when the closure trigger 18 is notlocked into the clamped position, the firing trigger 20 rotated awayfrom the pistol grip portion 26 of the handle 6 such that the front face242 of the upper portion 230 of the firing trigger 20 is not in contactwith the proximate end of the threaded rod 266. When the operatorretracts the closure trigger 18 and locks it in the clamped position,the firing trigger 20 rotates slightly towards the closure trigger 18 sothat the operator can grasp the firing trigger 20, as shown in FIG. 38.In this position, the front face 242 of the upper portion 230 contactsthe proximate end of the threaded rod 266.

As the user then retracts the firing trigger 20, after an initialrotational amount (e.g., 5 degrees of rotation) the run motor sensor 110may be activated such that, as explained above, the sensor 110 sends asignal to the motor 65 to cause it to rotate at a forward speedproportional to the amount of retraction force applied by the operatorto the firing trigger 20. Forward rotation of the motor 65 causes themain drive shaft 48 to rotate via the gear drive train, which causes theknife 32 and sled 33 to travel down the channel 22 and sever tissueclamped in the end effector 12. The control circuit receives the outputsignals from the encoder 268 regarding the incremental rotations of themain drive shaft assembly and sends a signal to the second motor 265 tocause the second motor 265 to rotate, which causes the threaded rod 266to retract into the motor 265. This allows the upper portion 230 of thefiring trigger 20 to rotate CCW, which allows the lower portion 228 ofthe firing trigger to also rotate CCW. In that way, because thereciprocating movement of the threaded rod 266 is related to therotations of the main drive shaft assembly, the operator of theinstrument 10, by way of his/her grip on the firing trigger 20,experiences tactile feedback as to the position of the end effector 12.The retraction force applied by the operator, however, does not directlyaffect the drive of the main drive shaft assembly because the firingtrigger 20 is not geared into the gear drive train in this embodiment.

By virtue of tracking the incremental rotations of the main drive shaftassembly via the output signals from the encoder 268, the controlcircuit can calculate when the knife 32 is fully deployed (e.g., fullyextended). At this point, the control circuit may send a signal to themotor 65 to reverse direction to cause retraction of the knife 32. Thereverse direction of the motor 65 causes the rotation of the main driveshaft assembly to reverse direction, which is also detected by theencoder 268. Based on the reverse rotation detected by the encoder 268,the control circuit sends a signal to the second motor 265 to cause itto reverse rotational direction such that the threaded rod 266 starts toextend longitudinally from the motor 265. This motion forces the upperportion 230 of the firing trigger 20 to rotate CW, which causes thelower portion 228 to rotate CW. In that way, the operator may experiencea CW force from the firing trigger 20, which provides feedback to theoperator as to the retraction position of the knife 32 in the endeffector 12. The control circuit can determine when the knife 32 isfully retracted. At this point, the control circuit may send a signal tothe motor 65 to stop rotation.

According to other embodiments, rather than having the control circuitdetermine the position of the knife 32, reverse motor and stop motorsensors may be used, as described above. In addition, rather than usinga proportional sensor 110 to control the rotation of the motor 65, anon/off switch or sensor can be used. In such an embodiment, the operatorwould not be able to control the rate of rotation of the motor 65.Rather, it would rotate at a preprogrammed rate.

FIG. 43 is a partial cross-sectional view of a surgical instrument 300with various components removed for clarity. The surgical instrument 300has a rack 302 (shown in cross-section) for driving an end effector (notshown). A pinion gear 304 engages with the rack 302 such that rotationof the pinion gear 304 in a CCW direction distally translates the rack302 and rotation of the pinion gear 304 in the CW direction proximallytranslates the rack 302. The pinion gear 304 may rotate about an axel306 and may be driven by a motor which is operationally controlled by atrigger (not shown). In one embodiment, the pinion gear 304 may bebiased in a first direction 303 by a biasing member 308. The biasingmember 308 may be a spring, as illustrated, although any other suitablebiasing technique may be used. The surgical instrument 300 may comprisea lever 310 that may be used, for example, in the event the energy levelof the surgical instrument's power source falls below sufficientoperational levels. In one embodiment, the level 310 is generallyconcealed from the user by a door 312, which may be removed by the userto access the lever 310. The lever 310 may be rotatable about a pivot314 in a direction indicated by arrow 316. A locking cam 318 may beattached to the lever 310 such that rotation of the lever 310 about thepivot 314 rotates the locking cam 318. In some embodiments, the lockingcam 318 is unitary with the lever 310.

FIGS. 44A and 44B illustrate the locking cam 318 during various statesof operation. The locking cam 318 comprises a body portion 320 and aspring portion 322 that may pivot, or otherwise flex, with respect tothe body portion 320 about a hinge portion 324. The hinge portion 324may comprise, for example, a living hinge. In one embodiment, the bodyportion 320 and the spring portion 322 are unitary and formed from asingle piece of material. The locking cam 318 may define a clearance 326that allows the spring portion 322 to pivot toward the body portion 320.The spring portion 322 may have a tooth 331 that is received by a notch321 in the body portion 320. On their respective outer peripheries, thebody portion 320 may have a first contacting surface 328 and the springportion 322 may have a second contacting surface 330. In the closedposition (FIG. 44A), the first contacting surface 328 is generallyaligned with the second contacting surface 330 such that the outerperiphery of the locking cam 318 has a generally continuous cammedsurface. In the open position (FIG. 44B), the spring portion 322 pivotsaway from the body portion 320 to increase the clearance 326. A gap 332is created between the first contacting surface 328 and the secondcontacting surface 330.

Referring now to FIGS. 43, 44A, and 44B, upon rotation of the lever 310in the direction indicated by arrow 316, the locking cam 318 is rotatedand the second outer surface 330 of the spring portion 322 firstcontacts a top surface 342 of the pinion gear 304. As a result of thiscontact, the spring portion 322 is pivoted toward the body portion 320to create a generally continuous periphery. As the locking cam 318continues to rotate, the second contacting surface 330 and then thefirst contacting surface 328 exerts force on the pinion gear 304 toovercome the biasing force applied by the biasing member 308. As aresult, the pinion gear 304 is pushed in the direction indicated byarrow 324 as the lever 310 is rotated in the direction indicated byarrow 316. The movement of the pinion gear 304 decouples it from therack 320 allowing the rack 320 to translate freely. Once the springportion 322 clears the top surface 342 of the pinion gear 304, it pivotsto the open position (FIG. 44B) to lock the locking cam 318 into place.Once in the open position, the locking cam 318 will be impeded fromrotating in the direction indicated by arrow 344 (FIG. 43) due to theengagement of the spring portion 322 with the pinion gear 304.

FIGS. 45A, 45B, and 45C show a locking cam 418 and a gear 404 duringthree stages of operation. Various components have been removed and/orsimplified for clarity. As illustrated, the locking cam 418 may bemanufactured from a single piece of material. The locking cam 418comprises a spring portion 422 that is pivotable with respect to a bodyportion 420. FIG. 45A shows the locking cam 418 in a non-engagedposition. In this position, a distal portion 423 of the spring portion422 is separated from the body portion 420. As illustrated in FIG. 45B,when the locking cam 418 is rotated in the direction indicated by arrow416, the spring portion 422 is drawn toward the body portion 420 tocreate a generally continuous periphery spanning the spring portion 422and the body portion 420. As the locking cam 418 contacts a central hub442, the pinion gear 404 moves in the direction indicated by arrow 443.As the locking cam 418 continues to rotate in the direction indicated byarrow 416, eventually the spring portion 422 passes over the central hub442. As shown in FIG. 45C, when the distal portion 423 of the springportion 422 separates from the body portion 420, it engages the teeth ofthe pinion gear 404 to lock the locking cam 418 into an engagedposition. Accordingly, in various embodiments, while the locking cam 418may be made from a single piece of material, it may function as twoparts (e.g., a cam and a locking mechanism).

FIG. 46 illustrates one embodiment of a surgical instrument 500. Theinstrument 500 comprises a handle 502, a pistol grip 501, a trigger 504and an end effector 505. According to various embodiments, the handle502, trigger 504 and end effector 505 may operate in a manner similar tothat of the various handles 6, triggers, 18, 20 and end effectors 12described herein. In addition to, or instead of, the functionalitydescribed herein above, the end effector 501 may comprise surgicalimplements for cutting, clasping, laser cutting and/or coagulation, RFcutting and/or coagulation, ultrasonic cutting and/or coagulation, forexample.

The handle 502 of the instrument 500 may house at least one battery unit506. The battery unit 506 may comprise a single battery or a pluralityof batteries arranged in a series and/or parallel configuration. Thehandle 502 may comprise a battery dock 508 to which the battery unit 506may be attached. The battery dock 508 may be any suitable structure forcoupling the battery unit 506 to the instrument 500. For example, thebattery dock 508 may be a cavity in the handle 502 configured to receiveat least a portion of the battery unit 506, as illustrated. In otherembodiments, the battery dock 508 may be implemented using a variety ofother structures. In one embodiment, the battery dock 508 is a post thatis received by the battery unit 506. In one embodiment, the pistol grip501 comprises the battery dock 508. In any event, as discussed in moredetail below, the battery dock 508 may comprise a protruding portion tointeract with the battery unit 506 upon attachment of the battery unit506 to the handle 502. Once attached, the battery unit 506 may beelectrically connected to and may provide power to a circuit 514 of theinstrument 500. The circuit may be located in the handle 502, as shown,in the end effector 505, or in any combination of locations within theinstrument 500. In use, the circuit 514 may power the operation of atleast one surgical implement at the end effector 505. For example, thecircuit 514 may comprise an electric motor for operating an electricallypowered cutter, clasper, or other mechanical device. In addition to, orinstead of a motor, the circuit 514 may comprise suitable circuitcomponents for implementing an RF, ultrasonic, or other type ofnon-motor-powered surgical implement.

FIGS. 47A, 47B, 47C schematically illustrate the battery unit 506 and aportion of the instrument 500. The battery unit 506 may comprise a drainthat automatically completes a circuit within the battery unit 506 uponattachment to the instrument 500. The drain serves to slowly reduce thecharge of the battery unit 506 over time. Once the battery unit 506 hasbeen sufficiently drained it may be disposed as non-hazardous waste, forexample. The battery unit 506 may comprise a voltage source 510. In oneembodiment, the voltage source 510 is a lithium battery and comprises atleast one cell selected from the group consisting of a CR123 cell and aCR2 cell. As is to be appreciated, any suitable voltage source may beused. The battery unit 506 also comprises a drain 512 that iselectrically coupled to the voltage source 510 when a switch 516 isclosed. The battery unit 506 and the instrument 500 each compriseelectrically conductive contacts 518, 520, respectively, that are placedinto contact upon attachment of the battery unit 506 to the instrument500. FIG. 47A illustrates the battery in a non-attached position. Theswitch 516 is in an open position and the voltage source 510 may be in afully charged condition. FIG. 47B illustrates that battery unit 506 inan attached position. The conductive contacts 518 of the battery unit506 are in electrical communication with the contacts 520 of theinstrument thereby allowing the battery unit 506 to supply energy to thecircuit 514 (FIG. 46). In the attached position, the switch 516transitions to the closed position to electrically couple the voltagesource 510 to the drain 512. Energy will flow from the voltage source510 through the drain 512 during operation of the instrument. In otherwords, the drain 512 will be draining the charge from the voltage source510 concurrently as the battery unit 506 is supplying operational powerto the instrument 500. As discussed in more detail below, a portion ofthe instrument 500 may physically interact with the drain 512 duringattachment of the battery unit 506 to the instrument 500 to transitionthe switch 516 from the open to the closed state. FIG. 47C illustratesthe battery unit 506 in a non-attached position. In one embodiment, theswitch 516 remains in the closed position to continue to drain thevoltage source 510 even after the battery unit 506 has been detachedfrom the instrument 500.

FIG. 48 is a graph 600 of the voltage level of the battery unit 506 overtime, as measured from the time of attachment to the instrument 500, inaccordance with one non-limiting embodiment. The graph 600 isillustrates the voltage levels of a 6V cell of the battery unit 506. Thegraph 600 is merely representative of one embodiment of the battery unit506. As is to be appreciated, while the graph 600 illustrates a 6 VDCpower supply, the battery unit 506 may supply any suitable voltage, suchas 9 VDC, 12 VDC or 18 VDC, for example. As discussed in more detailbelow, the battery unit 506 may comprise multiple cells arranged in aparallel and/or series configuration. The graph 600 includes threeexample discharge curves 602, 604, 606. As illustrated by the firstdischarge curve 602, the voltage of the power source 510 drops below 2.0volts after around 28 hours. As illustrated by the second dischargecurve 604, the voltage of the power source 510 drops below 2.0 voltsafter around 30 hours. As illustrated by the third discharge curve 606,the voltage of the power source 510 drops below 2.0 volts after around33 hours. The overall shape of the discharge curve may depend upon, forexample, the level of activity of the instrument 500 during the surgicalprocedure. For example, the instrument associated with the firstdischarge curve 602 was more heavily used during the surgical procedurethan the instrument associated with discharge curve 606. In any event,the drain 512 maintains the voltage level of the battery unit 506 at asatisfactory level for a certain time period to ensure that theinstrument can be used for its intended purpose during the course of thesurgical procedure. For example, in one embodiment, the voltage level ofthe battery unit 506 is maintained around 6 volts for approximately 12hours. After 12 hours, the voltage level gradually decreases to anon-hazardous level. As is to be appreciated, the drain 512 may becalibrated to deplete the voltage source faster or slower.

In one embodiment, a resistive element is use to reduce the energy levelof the voltage source. FIG. 49A is a simplified circuit diagram of abattery unit 616 comprising a drain 612. The battery unit 616 may beattached to an instrument 500, for example, via its contacts 618. Inthis embodiment, the battery unit 616 comprises a first grouping ofcells 610 and a second grouping of cells 611. In one embodiment, thefirst and second grouping of cells 610, 611 are lithium batteries. Thefirst and second grouping of cells 610, 611 may each have a plurality ofseparate cells 610 a, 610 b, 611 a, 611 b arranged in a parallelformation. For example, the first and second grouping of cells 610, 611may each be 6 VDC and arranged in a series configuration to produce 12VDC at the contacts 618 of the battery unit 616 when fully charged. Thecells 610 a, 610 b, 611 a, 611 b, however, may be electrically connectedto one another in series or parallel or any other combination thereof.

In one embodiment, the drain 612 comprises a first resistive element 622and a second resistive element 624. As is to be appreciated, in someembodiments, the battery unit 616, may comprise, for example, multipledrains 612 each having more or less than two resistive elements or othercircuitry. In the illustrated embodiment, the first resistive element622 is coupled across a first anode 626 and a first cathode 628 of thefirst grouping of cells 610 through a first switch 630. The firstresistive element 624 may be coupled across a second anode 632 and asecond cathode 634 of the second grouping of cells 611 through a secondswitch 636. The first and second switches 630, 636 may be closed uponattachment of the battery unit 616 to the surgical instrument 500 inorder to initiate the draining of the first and second grouping of cells610, 611.

The value of the resistive elements utilized by the drain 612 may varybased on implementation. In one embodiment, the first resistive element622 has a resistance in the range of about 90 ohms to about 110 ohms. Inone embodiment, the first resistive element 622 has a resistance in therange of about 97 ohms to about 104 ohms. In one embodiment, theresistive element 622 is 102.9 ohms and has a power rating of 1 watt.The determination of the necessary resistance is based at leastpartially on the capacity of the voltage source, the voltage level ofthe voltage source, and the desired temporal length of the drainagecurve. For example, in one embodiment the battery capacity of the firstgrouping of cells 610 is 1400 mAh, the voltage level is 6 VDC, and thetarget drain time is 24 hours. Diving 1400 mAh by 24 hours yields acurrent of 0.0582 A. Using Ohm's law, 6 V divided by 0.582 A yields aresistance of 102.9 ohms. With a current of 0.583 and a resistance of102.9 ohms, the power dissipated by the resistor is 0.350 W. As is to beappreciated, different voltage levels, battery capacities, and desiredtime of discharge will result in different resistance values.

FIG. 49B is a simplified circuit diagram of yet another embodiment of abattery unit. In FIG. 49B, a battery unit 660 is attachable to asurgical instrument 650 having multiple sets of contacts. Asillustrated, the surgical instrument 650 has a first set of contacts652A, 652B and a second set of contacts 654A, 654B. The battery unit 660has a first set of contacts 656A, 656B and a second set of contacts658A, 658B configured to engage the contacts of the surgical instrument650. In the illustrated embodiment, the battery unit 660 comprises afirst cell 662 in series with a second cell 664 that supply power to thesurgical instrument 650 through its first set of contacts 652A, 652B.The battery unit 660 may also comprises a third cell 668 in series witha fourth cell 670 that supply power to the surgical instrument 650through its second set of contacts 654A, 654B. The first, second, thirdand fourth cells 662, 664, 668, 670 may each provide any suitablevoltage level when fully charged, such as 3 VDC or 6 VDC, for example.In one embodiment, the battery unit 660 delivers a total of about 12 VDCto the surgical instrument 650 when the battery unit is fully charged(e.g., about 6 VDC via the first set of contacts 656A, 656B and about 6VDV via the second set of contacts 658A, 658B). The battery unit 660 maycomprise a first drain 672 and a second drain 674. While the first drain672 and the second drain 674 are schematically illustrated separately inFIG. 49A, it is to be appreciated that the drains 672 and 674 may beimplemented on a single circuit board, or through any other suitableimplementation. The first drain 672 comprises a first resistive element674 that is connected in a series arrangement with the first and secondcells 662, 664 and a first switch 680. The second drain 674 comprises asecond resistive element 682 that is connected in a series arrangementwith the third and fourth cells 668, 670 and a second switch 684. Thefirst and second switches 680, 684 are illustrated in an open position.When the first switch 680 is closed (e.g., during attachment of thebattery unit 660 to the surgical instrument 650), current flows from thefirst and second cells 662, 664 through the first resistive element 678to discharge those cells. Similarly, when the second switch 684 isclosed (e.g., during attachment of the battery unit 660 to the surgicalinstrument 650), current flows from the third and fourth cells 668, 670through the first resistive element 678 those cells.

FIG. 50 is a simplified circuit diagram of a battery unit 716 comprisinga first drain 712 and a second drain 713. The battery unit 716 may beattached to an instrument 500, for example, via its contacts 718. Inthis embodiment, the battery unit 716 comprises a first grouping ofcells 710, a second grouping of cells 711, and a third cell 714. Thefirst drain 712 comprises a first resistive element 722 and a secondresistive element 724. The second drain 713 comprises a third resistiveelement 726. The resistive elements 722, 724, 726 are coupled torespective cells through switches 730, 736, and 738. The switches 730,736, and 738 may be closed upon attachment of the battery unit 716 tothe surgical instrument 500 in order to initiate the draining of thefirst and second grouping of cells 610, 611 and the third cell 716. Theresistance of the third resistive element 726 may be similar ordifferent from the resistances of the first and second resistive element722, 724. As described above, the resistance of the third resistiveelement 726 may at least partially depend on the voltage of the thirdcell 714 and the desired characteristics of the drainage curve.

FIGS. 51-53 are perspective views of a battery unit 800 implementing theschematic of the battery unit 616 shown in FIG. 49. The battery unit 800may comprise a casing 802 defining an interior cavity 810. While theinterior cavity 810 is illustrated in a central portion of the casing802, it is to be appreciated that the internal cavity 810 may bepositioned in any suitable location. The casing 802 may be covered by acap 804 that may be secured to the casing 802 utilizing one or moremechanical latches 806, 808. FIG. 52 illustrates one embodiment of thebattery unit 800 with the cap 804 removed to show a plurality of cells812 within. Any suitable number and/or type of cells 812 may be used.For example, CR123 and/or CR2 cells may be used. FIG. 53 illustrates oneembodiment of the battery unit 800 with a portion of the casing 802removed to reveal the cells 812.

FIGS. 54A and 54B illustrate cross-sectional views of one embodiment ofthe battery unit 800 including a translatable drain 812. The drain 812may be positioned within the interior cavity 810 and may be translatablewithin the interior cavity 810 in the directions of arrow 815. FIG. 54Ashows the drain 812 in an open position and FIG. 54B shows the drain 812in a closed position. The drain 812 may comprise at least two contacts816, 818. When the drain 812 is in the open position, a portion of thecontacts 816, 818 may touch a non-conductive portion of the casing 802,such as fingers 820, 822. According to various embodiments, the contacts816, 818 may be biased to exert a force against the fingers 820, 822 inorder to resist movement of the drain 812 in the direction of the arrows815. Also, in some embodiments, the fingers 820, 822 may define one ormore protrusions or stepped down portions, as shown in FIGS. 54A and54B. The battery unit 800 may also comprise one or more electrodes, suchas first electrode 824 and second electrode 826. The first and secondelectrodes 824 and 826 may each be electrically coupled to a cathode oran anode of cells contained within the battery unit 800. In the closedposition (FIG. 54B), the contacts 816, 818 are in electrical connectionwith the electrodes 824, 826, thereby allowing the voltage source todischarge through the drain 812. As discussed in more detail below, thedrain 812 may be translated from the open position to the closedposition upon attachment of the battery unit 800 to a surgicalinstrument.

FIG. 55 is a perspective view of the drain 812 in accordance with onenon-limiting embodiment. The contacts 816, 818 of the drain 812 may becoupled to a base portion 830 of the drain 812. Similarly contacts 836,838 of the drain 812 may be coupled to the base portion 830 of the drain812. According to various embodiments, the contacts 816, 818 may beelectrically connected to one another via a resistive element (notshown) mounted to a circuit board 832. Similarly, the contacts 836, 838may be electrically connected to one another via a resistive elementmounted to the circuit board 832. As illustrated, the contacts 816, 818,836, 838 may have a bend or curvature to bias the contacts towards anoutward position when they are inwardly compressed. Additionally, in oneembodiment, the distal end of each of the contacts 816, 818, 836, 838may have an inwardly turned section. The base portion 830 may comprise acontacting surface 840 that engages the instrument when the battery unit800 is attached to the instrument. Through this engagement, the drain812 may be translated relative to the casing 800.

FIG. 56 illustrates the battery unit 800 attached to a battery dock 850.For clarity, various components have been removed. Referring now toFIGS. 54A, 54B, 55 and 56, the battery dock 850 comprises a protrudingmember 858 sized to be received by the cavity 810 (FIG. 51) of thebattery unit 800. Prior to attachment, the drain 812 is in the openposition (FIG. 54A). During attachment of the battery unit 800 to thebattery dock 850, the protruding member 858 is inserted into the cavity810 and the battery unit 800 is moved relative to the battery dock 850in the direction indicated by arrow 862. Eventually the distal end 860of the protruding member 858 contacts the contacting surface 840 of thedrain 812. As the user continues to attach the battery unit 800, thedrain 812 is translated relative to the casing 802 in the directionindicated by arrow 864 and moves into the closed position (FIG. 54B). Inthis position, the battery unit 800 commences to slowly drain. When thebattery unit 800 is removed from the battery dock 850, the drain 812 mayremain in the position shown in FIG. 54B. In this way, the cells (notshown) of the battery unit 800 may drain any remaining charge across aresistive element either before or during disposal.

As is to be appreciated, the translatable discharge drain of the batteryunit is not limited the implementation illustrated in FIG. 56. FIGS. 57Aand 57B, for example, illustrate a battery unit 900 and drain 912 withvarious components removed for clarity. The drain 912 that istranslatable between an open position (FIG. 57A) and a closed position(FIG. 57B). In the open position, contacts 916, 918 are engaged withnon-conductive portions of a casing 920, 922, respectively. The drain912 may ride in a track 914 when translating between the open positionand the closed position. FIG. 57B shows the battery unit 900 in a closedposition after a ram 958 has translated the drain 912 in the directionindicated by arrow 964. The ram 958 may be a component of a battery dockof a surgical instrument, for example. In one embodiment, the batterydock comprises a cavity that is dimensioned to receive the battery unit900, and the ram 958 is positioned within the cavity. In the closedposition, the contacts 916, 918 are in electrical contact withelectrodes 924, 926. The drain 912 may comprise a printed circuit board932 to which at least one resistive element is mounted using a surfacemount or a through-hole connection, for example.

FIGS. 58A and 58B illustrate a battery unit 1000 in accordance withanother non-limiting embodiment. Various components have been omittedfor clarity. The battery unit 1000 comprises a drain 1012 that istranslatable between an open position (FIG. 58A) and a closed position(FIG. 58B). The battery unit 1000 may comprise a first electrode 1024with a contact 1025 and a second electrode 1026 with a contact 1027. Theelectrodes 1024, 1026 may be in contact with cells (not shown) of thebattery unit 1000. In the open position, contacts 1016, 1018 of thedrain 1012 are not engaged with contacts 1025, 1027 of the electrodes1024, 1026. The drain 1012 may ride in a track 1014 when translatingbetween the open position and the closed position. FIG. 58B shows thebattery unit 1000 in a closed position after a ram 1058 has translatedthe drain 1012 in the direction indicated by arrow 1064. The ram 1058may be a component of a battery dock of a surgical instrument, forexample. In the closed position, the contacts 1016, 1018 of the drain1012 are in electrical contact with the contacts 1025, 1027 of theelectrodes 1024, 1026. The drain 1012 may comprise a printed circuitboard 1032 that includes at least one resistive element. In someembodiments, the contacts 1016, 1018 themselves may comprise theresistive elements. In fact, the resistive elements may be elements ofany suitable resistance value and any suitable mechanical configuration.

FIG. 59 is a perspective view of a battery unit 1100. FIGS. 60A and 60Bshow internals views of the battery unit 1100 during various stages ofoperation with various components removed for clarity. The battery unit1100 has one cell 1102 and an outer casing 1104 that defines a cavity1110. The outer casing 1104 may be non-conductive and have conductivecontacts for supplying energy to circuitry of a surgical instrument whenthe battery unit 1100 is attached to a surgical instrument. In oneembodiment, the battery unit 1100 is received by a cavity in a pistolgrip portion of a surgical instrument. The battery unit 1100 comprises adrain 1112 that is translatable between an open position (FIG. 60A) anda closed position (FIG. 60B). In one embodiment the drain 1112 has firstand second contacts 1116, 1118 that are coupled to a circuit board 1132.The circuit board 1132 may include, for example, at least one resistiveelement. In some embodiments, the circuit board 1132 includes additionalcircuitry. The battery unit 1100 comprises a first electrode 1124coupled to an anode of the cell 1102 and a second electrode coupled to acathode of the cell 1102. Before the battery unit 1100 is attached to aninstrument, the drain 1112 is in the open position (FIG. 60A). In theillustrated embodiment, the first contact 1116 is electrically coupledto the first electrode 1124 and the second contact 1118 is resting on,or otherwise contacting, a non-conductive finger 1120. As the batteryunit 1100 is attached to an instrument, a protruding portion 1158 of theinstrument may be received by the cavity 1110 and contact the drain 1112to drive the drain 1112 in the direction indicated by the arrow 1164. Inthe closed position (FIG. 60B) the first contact 1116 is electricallycoupled to the first electrode 1124 and the second contact 1118 iselectrically coupled to the second electrode 1126. In this position, aclosed circuit is created that allows the cell 1102 to discharge energythrough the drain 1112.

Additional details regarding surgical instruments and battery units aredescribed in U.S. patent application Ser. No. 12/884,838, entitled“SURGICAL INSTRUMENTS AND BATTERIES FOR SURGICAL INSTRUMENTS,” filedSep. 17, 2010, and incorporated herein by reference in its entirety.

It is to be understood that at least some of the figures anddescriptions herein have been simplified to illustrate elements that arerelevant for a clear understanding of the disclosure, while eliminating,for purposes of clarity, other elements. Those of ordinary skill in theart will recognize, however, that these and other elements may bedesirable. However, because such elements are well known in the art, andbecause they do not facilitate a better understanding of the disclosure,a discussion of such elements is not provided herein.

While several embodiments have been described, it should be apparent,however, that various modifications, alterations and adaptations tothose embodiments may occur to persons skilled in the art with theattainment of some or all of the advantages of the disclosure. Forexample, according to various embodiments, a single component may bereplaced by multiple components, and multiple components may be replacedby a single component, to perform a given function or functions. Thisapplication is therefore intended to cover all such modifications,alterations and adaptations without departing from the scope and spiritof the disclosure as defined by the appended claims.

Any patent, publication, or other disclosure material, in whole or inpart, that is said to be incorporated by reference herein isincorporated herein only to the extent that the incorporated materialsdoes not conflict with existing definitions, statements, or otherdisclosure material set forth in this disclosure. As such, and to theextent necessary, the disclosure as explicitly set forth hereinsupersedes any conflicting material incorporated herein by reference.Any material, or portion thereof, that is said to be incorporated byreference herein, but which conflicts with existing definitions,statements, or other disclosure material set forth herein will only beincorporated to the extent that no conflict arises between thatincorporated material and the existing disclosure material.

1-20. (canceled)
 21. A surgical system comprising: a surgical devicecomprising a battery dock; a battery unit comprising at least onebattery cell; and a battery drain wherein, in a first state, the batterydrain is not electrically coupled to the at least one battery cell,wherein, in a second state, the battery drain is electrically coupled tothe at least one battery cell to discharge the at least one batterycell, and wherein the battery drain transitions from the first state tothe second state upon attachment of the battery unit to the batterydock.
 22. The surgical system of claim 21, wherein the battery unitcomprises at least one switch, wherein the at least one switch has afirst switch position in which the battery drain is not electricallycoupled to the at least one battery cell and a second switch stateposition in which the at least one switch electrically couples thebattery drain to the at least one battery cell to discharge the at leastone battery cell.
 23. The surgical system of claim 22, wherein the atleast one switch is transitioned from the first switch position to thesecond switch position upon attachment of the battery unit to thebattery dock, and wherein the at least one switch is configured toremain in the second switch position after detachment of the batteryunit from the battery dock.
 24. The surgical system of claim 22, whereinthe at least one battery cell comprises a first battery cell and asecond battery cell, and wherein the at least one switch comprises afirst switch and a second switch.
 25. The surgical system of claim 24,wherein when the at least one switch is in the first switch position,the first switch and the second switch are open, and wherein when the atleast one switch is in the second switch position, the first switch isclosed to electrically couple a first portion of the battery drain tothe first battery cell to discharge the first battery cell and thesecond switch is closed to electrically couple a second portion of thebattery drain to the second battery cell to discharge the second batterycell.
 26. The surgical system of claim 21, wherein the battery drain isat a first position within the battery unit when in the first state andat a second position within the battery unit when in the second state.27. The surgical system of claim 26, wherein the battery unit defines afirst electrode and a second electrode, wherein the battery draincomprises a first contact and a second contact, and wherein, when thebattery drain is in the second position within the battery unit thefirst and second contacts are in electrical communication with the firstand second electrodes to electrically couple the battery drain to the atleast one battery cell to discharge the at least one battery cell. 28.The surgical system of claim 27, wherein, when the battery drain is inthe first position within the battery unit, the first and secondcontacts are in contact with a non-conductive portion of the batteryunit.
 29. The surgical system of claim 27, wherein the battery dockdefines a protruding member extending along a protrusion axis andpositioned such that, upon attachment of the battery unit to the batterydock, the protruding member contacts the battery drain and transitionsthe battery drain from the first position to the second position. 30.The surgical system of claim 29, wherein the first and second electrodesare positioned on a surface of the battery unit that is substantiallyparallel to the protrusion axis.
 31. The surgical system of claim 30,wherein the first and second contacts extend substantially parallel tothe protrusion axis.
 32. The surgical system of claim 29, wherein thefirst and second electrodes are positioned on a surface of the batteryunit that is substantially perpendicular to the protrusion axis.
 33. Thesurgical system of claim 32, wherein the first and second contactsextend substantially parallel to the protrusion axis.
 34. The surgicalsystem of claim 26, wherein the battery dock defines a protruding memberpositioned to be received into the battery unit when the battery unit isattached to the battery dock, wherein the protruding member transitionsthe battery drain from the first position to the second position. 35.The surgical system of claim 26, wherein the at least one battery cellcomprises a first battery cell and a second battery cell, wherein thebattery unit defines a first electrode, a second electrode, a thirdelectrode and a fourth electrode, wherein the battery drain comprises afirst contact, a second contact, a third contact and a fourth contactand wherein, when the battery drain is in the second position within thebattery unit: the first and second contacts are in electricalcommunication with the first and second electrodes to electricallycouple the battery drain to the first battery cell to discharge thefirst battery cell; and the third and fourth contacts are in electricalcommunication with the third and fourth electrodes to electricallycoupled the battery drain to the second battery cell to discharge thesecond battery cell.
 36. A surgical system comprising: a surgical devicecomprising a battery dock; a battery unit comprising at least onebattery cell; and a battery drain wherein, in a first position, thebattery drain is not in electrical communication with the at least onebattery cell, wherein, in a second position, the battery drain iselectrically coupled to the at least one battery cell to discharge theat least one battery cell, and wherein the battery drain transitionsfrom the first position to the second position upon attachment of thebattery unit to the battery dock.
 37. The surgical system of claim 36,wherein the battery unit defines a first electrode and a secondelectrode, wherein the battery drain comprises a first contact and asecond contact, and wherein, when the battery drain is in the secondposition within the battery unit the first and second contacts are inelectrical communication with the first and second electrodes toelectrically couple the battery drain to the at least one battery cellto discharge the at least one battery cell.
 38. The surgical system ofclaim 37, wherein, when the battery drain is in the first positionwithin the battery unit, the first and second contacts are in contactwith a non-conductive portion of the battery unit.
 39. A surgical systemcomprising: a surgical device; at least one battery cell; and a batterydrain, wherein the surgical system defines a first state where thebattery drain is not electrically coupled to the at least one batterycell and a second state where the battery drain is electrically coupledto the at least one battery cell to discharge the at least one batterycell, and wherein the battery drain transitions from the first state tothe second state upon attachment of the battery unit to the batterydock.
 40. The surgical system of claim 39, wherein the surgical systemcomprises at least one switch, wherein the at least one switch has afirst switch position in which the battery drain is not electricallycoupled to the at least one battery cell and a second switch stateposition in which the at least one switch electrically couples thebattery drain to the at least one battery cell to discharge the at leastone battery cell.